Kourtney Kardashian shares slim post-baby weight with a pic of her scale

Kourtney Kardashian hasn’t seen this number on the scale in a long time: 120 pounds.

(And neither have we, but that’s beside the point.)

The eldest Kardashian sister, who welcomed her third child, Reign, in December with boyfriend Scott Disick, shared her post-baby weight on Instagram showing her scale reading 120.00.

“First day that I have seen this number in a while,” the 5-foot-tall star wrote on Friday, adding several celebratory emojis.

PHOTOS: Meet the Kardashians and their extended family

The reality star stepped out with half-sister Kendall Jenner on Saturday when they attended Comedy Central’s roast of Justin Bieber at Sony Pictures Studios in Culver City. (The show airs on the network March 30.)

“My obsession with these people is not normal! #justinbieberroast,” the 35-year-old added, posting a group shot including Jenner, Bieber pal Jaden Smith and “Workaholics” actor Blake Anderson.

The sisters heard an earful from the dais of roasters about Jenner’s alleged relationship with the “Baby” singer and several barbs about Kardashian patriarch Bruce Jenner’s rumored sex change.

“If you were going to be with a Jenner, I thought it’d be Bruce,” emcee Kevin Hart quipped, before turning to the reality stars seated in the audience. “I love you Kourtney -- she’s gonna hit me later.”

Later, Will Ferrell, who made a surprise appearance as his “Anchorman” alter-ego Ron Burgundy, referred to Bruce Jenner as a “Hollywood hermaphrodite.”

Follow me on Twitter @NardineSaad.